1. Field of the Invention
The invention relates to a method, apparatus and communication system for estimating an ON-OFF traffic characteristic used in quality evaluation of a packet data communication and a recording medium recording a program for estimating an ON-OFF traffic characteristic.
2. Description of Related Art
Generally, a packet loss ratio, a maximum value of a delay time, or a delay time variance is used as an indicator representing a service quality of a packet data communication network.
In high-speed data transfer such as real-time transfer of moving picture data, a data transfer rate mostly represents a pattern called an ON-OFF traffic in which a high-speed transfer period and a non-transfer period are repeated.
As a related art of the invention, there is a communication quality measuring apparatus which computes a network traffic measurement value at a predetermined time interval, computes a load index as a long-term measurement average value of the measurement value and a timing index as a moving average value of the measurement value, and performs control to generate or stop a test packet for communication quality measurement of an IP network according to the load index and the timing index (for example, see Japanese Patent Application Laid-Open No. 2005-236909).
As another related art of the invention, there is a technique in which a packet arrival to each session is modelized by a periodic on off process, and a packet in which a violation probability, which is a probability which will be delayed longer than a designated delay limit, is larger than a designated threshold is refused and not accepted by a server (for example, see Japanese Patent Application Laid-Open No. 2001-285344).
Next, problems of the related arts described above will be described.
In an ON-OFF traffic described above, compared to a traffic in which a data transfer rate is almost constant, even though an average data transfer rate is the same, a packet loss ratio becomes larger, and a delay time variance becomes larger. In addition, even in a communication with any other terminal which shares a resource of a network node, a packet loss ratio is increased and a delay time variance becomes larger. Accordingly, a network service quality deteriorates.
For this reason, in managing a network service quality, it is desirable to immediately estimate an ON-OFF traffic characteristic from a short-term real-time measurement value of a network traffic.
However, in order to analyze an ON-OFF traffic characteristic from a measurement value in real time, data analysis which accumulates measurement values for at least a predetermined time period and then performs large-scale computation through a high-performance measurement apparatus is necessary, whereby there is a problem in that the cost is increased even if it is realizable.
The techniques disclosed in JP-A Nos. 2005-236909 and 2001-285344 did not consider how to estimate an ON-OFF traffic characteristic from a short-term real time measurement value.